"People living in nearly 600 neighborhoods across the country are breathing concentrations of toxic air pollutants that put them at a much greater risk of contracting cancer, according to new data from the Environmental Protection Agency.

The levels of 80 cancer-causing substances released by automobiles, factories, and other sources in these areas exceed a 100 in 1 million cancer risk. That means that if one million people breathed air with similar concentrations over their lifetime, about 100 additional people would be expected to develop cancer because of their exposure to the pollution.

The average cancer risk across the country is 36 in one million, according to the National-Scale Air Toxics Assessment, which will be released by the EPA on Wednesday."